package com.链表;

/**
 * https://leetcode-cn.com/problems/partition-list/
 *给定一个链表和一个特定值 x，对链表进行分隔，使得所有小于 x 的节点都在大于或等于 x 的节点之前。
 *
 * 你应当保留两个分区中每个节点的初始相对位置。
 * 示例:
 *
 * 输入: head = 1->4->3->2->5->2, x = 3
 * 输出: 1->2->2->4->3->5
 */
public class 分隔链表 {
    public static ListNode partition(ListNode head, int x) {
        ListNode before_head = new ListNode(0);
        ListNode before = before_head;
        ListNode after_head =  new ListNode(0);
        ListNode after = after_head;

        while (head != null){
            if(head.val < x){
                before.next = head;
                before = before.next;
            }else{
                after.next = head;
                after = after.next;
            }
            head = head.next;
        }
       after.next = null;
        before.next = after_head.next;
        return before_head.next;
    }

    public static void main(String[] args) {
        ListNode l1 = new ListNode(new int[]{1,4,3,2,5,2});
        System.out.println(partition(l1,3));
    }
}
